1. Field of the Invention
This invention relates to a chair fastening device for attaching legs, arms and pedestal bases with or without control mechanisms to a chair and, more particularly to a slab base nut rivet for use in securing a metal bracket to a plastic seat pan of a chair without inducing stress fractures into the plastic.
2. Description of the Related Art
Fasteners are widely known in the art. The word "fastener" is a rather broad, generic term utilized so as to designate any device intended to be used in securing any article in place to another article. Various common fasteners or fastening devices include rivets, screws, bolts, nut elements, and the like which are used in connection with articles such as wood, metal, fabric, plastic and the like for any of a wide variety of diverse purposes.
It is extremely desirable to be able to install a fastener in such a manner that the fastener is incapable of relative movement with respect to the member upon which it is installed as well as resistant to torque caused by screwing a bolt into the fastener.
Previously, in the furniture industry, self-piercing "T-nuts" were utilized as fasteners in order to secure chair arms, legs or pedestal bases with or without control mechanisms to seat pans made of thin, flexible material such as plastic. However, the prongs of the "T-nut" would cause stress fractures in the plastic thus creating a rather weak attachment. Presently, weld nuts with slab base heads, commonly used as welded fastener inserts in metal products, were used in place of the self-piercing "T-nuts" but the slab base heads of the weld nuts could not be secured to the plastic seat pans without using a secondary operation such as gluing or stapling.
Consequently, there exists a need to secure a fastener such as a slab base weld nut to chair seat pans made of thin, flexible material such as plastic with drafted holes in such a way as to create a strong, secure attachment without the use of an elaborate secondary operation, while at the same time preventing torque rotation, preventing stress fractures, and resisting the entry force of screw installation into the fastener insert. It is the solution of this and other problems to which the present invention is directed.